2000 Millenia w/ Miller engine.

AC:
works great, only problem is when I turn the thermostat **** up to higher temp it doesn't have any affect on the coldness of air until I get to about 85 degrees, then it finally cools down and turns to warmer air.

Heat:
Generally doesn't work at all, blows air that's for sure but no heat. Every blue moon or so it'll magically turn on but only after the car has been turned off. This has only happened twice where the heat has come on when we've been trying to get it on for the past few months.

I checked the fuses under the hood and they all look ok.

 

Could be your thermostat is stuck open or a mode actuator sticking under the dash. Could also be a restricted heater core.

 

Ok thanks. Can you point me in the direction to check these items with easiest to hardes?

 

If your temp gauge is reading a bit lower than normal or it takes a long time to reach normal temp the t-stat could be stuck open. There are 2 hoses going through the firewall. Touch each of them at normal operating temp. If one is hot and the other cold the heater core is likely restricted. You may be able to disconnect those hoses and use a garden hose to flush it or go to a shop with a flush machine. You can look under the dash and move the heater control and locate the actuator that opens the door for heat. Bit difficult as it is tight in there. If you find the actuator for that door you can remove it and manually open the door for the winter months or until you get a replacement. If the actuator is not getting power then you may need a heater control unit. There are rebuilts available aftermarket and it is not an uncommon failure. It is however usually due to a faulty actuator.

 

I have a 2000 millenia and I had the same problem. I downloaded the repair manual for a 96 millenia, which is not exactly like the 2000 but here the site "http://rapidshare.com/files/51248650/Millenia-1996.rar". We took the radio out to see what we could find and at the same time my friend was reading over some things I had printed off. Come to find out it was the c/c computer needed to be reset. In order to do that you can find that on Pages U22-U26 of the manual. It was either that or it might have been where we took the negitive cable off the battery for about 2 minutes either way I have heat now without taking the dash out. If you can't download the manual let me know and I look at it again and explain it to you. Good Luck!